DS#attr()

attr (type, options) Attribute

DS.attr defines an attribute on a DS.Model. By default, attributes are passed through as-is, however you can specify an optional type to have the value automatically transformed. Ember Data ships with four basic transform types: string, number, boolean and date. You can define your own transforms by subclassing DS.Transform.

Note that you cannot use attr to define an attribute of id.

DS.attr takes an optional hash as a second parameter, currently supported options are:

defaultValue: Pass a string or a function to be called to set the attribute to a default value if none is supplied.

Example

app/models/user.js

import DS from 'ember-data';
 
export default DS.Model.extend({
  username: DS.attr('string'),
  email: DS.attr('string'),
  verified: DS.attr('boolean', { defaultValue: false })
});

Default value can also be a function. This is useful it you want to return a new object for each attribute.

app/models/user.js

import DS from 'ember-data';
 
export default DS.Model.extend({
  username: attr('string'),
  email: attr('string'),
  settings: attr({defaultValue: function() {
    return {};
  }})
});

The options hash is passed as second argument to a transforms' serialize and deserialize method. This allows to configure a transformation and adapt the corresponding value, based on the config:

app/models/post.js

export default DS.Model.extend({
  text: DS.attr('text', {
    uppercase: true
  })
});

app/transforms/text.js

export default DS.Transform.extend({
  serialize: function(value, options) {
    if (options.uppercase) {
      return value.toUpperCase();
    }
 
    return value;
  },
 
  deserialize: function(value) {
    return value;
  }
})

Parameters:

type String: the attribute type
options Object: a hash of options

Returns:

Attribute

Links:

http://emberjs.com/api/data#method_attr

doc_EmberJs

2025-01-10 15:47:30

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